1. Technical Field
This invention is generally related to games of skill and chance, and in particular to playing card games.
2. Description of the Related Art
Card games are a well-known form of recreation and entertainment. Games are typically played with one or more decks of cards, where each deck typically includes 52 cards. Each deck of cards will typically include four suits of cards, including: hearts, diamonds, clubs, and spades, each suit including fourteen cards having rank: 2-10, Jack, Queen, King and Ace. Card games may, or may not, include wagering based on the game""s outcome.
One popular card game is known as blackjack. In blackjack, one or more players each compete against a dealer. The players attempt to collect a hand having a total point value equal to, or as close to twenty-one, without going over. The point value of the hand is determined by the rank of the card. Thus, cards having rank 2-10 have the point value 2-10, respectively. Face cards (i.e., Jack, Queen, King) have the point value 10, while Aces can have the point value 1 or 11 at the player""s discretion. An initial hand of two cards having a point value of twenty-one (i.e., an Ace plus a ten or a face card) is referred to as a natural xe2x80x9c21xe2x80x9d, or blackjack, and beats other hands with the point value of twenty-one. Suits have no bearing on the game of blackjack.
In blackjack, the dealer initially deals two cards to each of the players in two passes around the table, starting with the player at the dealer""s far left (i.e., first base), extending through the player at the dealer""s far right (i.e., third base) and finally to the dealer""s self. The players"" cards are dealt face up in games where the cards are dealt from a shoe, and face down in hand-held games (i.e., games dealt by hand). The rules of play for the dealer are strictly dictated, leaving almost no decisions up to the dealer. Thus, the dealer, and other players, can see the other player""s hands without effecting the outcome of the game.
The dealer turns over or is dealt one of the dealer""s first two cards face up (i.e., top card), the rank of the card visible to the players at the table. The dealer leaves or is dealt the second card face down (i.e., hole card), the rank of the card not visible to the players at the table. In some variations of blackjack, the dealer will immediately determine the point value of the hole card, while in other variations of the game the dealer waits until all players have played their hands before checking the point value of the hole card.
The dealer then offers each player, in succession from the dealer""s left to right, the opportunity to accept additional cards. Each player""s hand is completed before the dealer offers the next player the opportunity to receive additional cards. Accepting cards is commonly referred to as xe2x80x9chittingxe2x80x9d or taking a xe2x80x9chit.xe2x80x9d At each player""s turn, the player may accept cards, one at a time, trying to build a hand with a point value as close to twenty-one as possible, without going over twenty-one. The player may decline further cards at anytime, which is commonly referred to as xe2x80x9cstanding.xe2x80x9d The player""s hand is immediately terminated if its point value exceeds twenty-one, which is commonly referred to as a xe2x80x9cbustxe2x80x9d or xe2x80x9cbusted.xe2x80x9d If the player busts, or has a natural twenty-one (i.e., blackjack), the dealer completes the player""s hand and place that player""s cards into a discard holder. Before receiving a third card after the initial hands are dealt, a player can split the player""s initial hand. This is commonly referred to as splitting. The player uses one of the initial cards to form a new hand, placing a wager for the new hand, and retains the other of the initial cards as a part of the original hand.
After each player in turn has declined to accept further cards, the dealer may accept further cards from the deck. Casinos have rules based on the point value of the dealer""s hand that dictate when the dealer must take an additional card from the deck (i.e., hit) and when the player must decline further additional cards (i.e., stand). For example, many casinos require the dealer to stand if the dealer""s hand has a point value of seventeen or more. Some, casinos permit the dealer to take an additional card if the point value of the dealer""s hand is a soft seventeen, that is, if the point value of the dealer""s hand is seventeen by counting an Ace held by the dealer as eleven.
If the dealer busts, players who have not also busted win. If the dealer does not bust, all remaining players and the dealer must display their hands to allow the dealer to compare each of the player""s hands to the dealer""s hand. Those players having a hand with a higher point value than the dealer""s hand, and who have not exceed twenty-one win. The winning players are paid based on the size of their wager and the odds. The wagers of losing players are collected, and the dealer collects the cards remaining on the table in a particular order. Blackjack includes additional rules such as xe2x80x9cdoubling downxe2x80x9d and xe2x80x9cinsurancexe2x80x9d bets, and other variations that are commonly known by those who play blackjack, and will not be further described in the interest of brevity.
Card games, such as twenty-one, are particularly popular in casinos and other gaming establishments. Players wager large sums of money while playing. Thus, it is important to ensure that those playing the game are not cheating. It is also important to monitor the game in a relatively unobtrusive manner to allow casino customers to feel comfortable in their surroundings.
Decks of playing cards must be periodically shuffled to prevent the cards from continually reappearing in the same order. Shuffling may also interfere with, and even prevent, a player from gaining an unfair advantage by counting cards. Numerous card counting systems are known, and typically rely on a player keeping a mental count of some or all of the cards which have been played. For example, in the game of twenty-one it is beneficial to determine when all cards with a rank of 5 have been dealt (i.e., fives strategy). Since cards with a value of ten favor the player over the house, it is also beneficial to determine the number of cards remaining in the deck(s) having a point value of ten (i.e., Tens strategy). Other variations of card counting are well known in the art. Shuffling may take place after every card in the deck or decks has been dealt, for example after several hands have been played, or may take place more frequently.
Manual shuffling tends to slow play down, so the gaming industry now employs mechanical shufflers to speed up play and to more thoroughly shuffle the cards. The cards are typically shuffled several cards before the end of the deck(s), in an effort to hinder card counting, which is particularly effective when only a few hands of cards remain (i.e., end game strategy). The ratio of the number of cards dealt to the total number of cards remaining in the deck(s) is commonly known as the deck penetration. The gaming industry is now introducing continuous shufflers in a further attempt to frustrate attempts at card counting. As the name implies, continuous shufflers mechanically shuffle the cards remaining to be dealt while one or more hands are being played.
While mechanical shufflers increase the speed of play and produce a more thorough shuffle than manual methods, mechanical shuffling is subject to incomplete shuffles due to the inherently consistent operation of mechanical devices and are limited in the total number of decks they can manipulate.
Under one aspect, a method of verifying playing card games includes automatically determining an identity of each of a number of playing cards forming a player""s completed hand; comparing the identity of each of the number of playing cards from the player""s completed hand to an expected set of playing cards for the player""s completed hand; and producing a notification if the identity of each of the number of playing card the player""s completed hand does not match a respective playing card in the expected set of playing cards for the player""s completed hand. In a related aspect, a computer-readable media can store instructions for causing a computer to verify playing card games by the method.
Under another aspect, a method of verifying playing card games employs a computationally generated pseudo-random sequence of playing card values. The method includes determining an expected set of playing card values for the playing card hand based on the computationally generated pseudo-random sequence of playing card values, a number of hands dealt and a relative position of the playing card hand in an order of dealing; and determining whether the identifiers read from each of the number of playing cards forming the hand of playing cards correspond to the expected set of playing card values for the playing card hand. The method can include generating the pseudo-random sequence of playing card values, or can include receiving a generated pseudo-random sequence of playing card values. The method can include reading an identifier from each of a number of playing cards forming a hand of playing cards, or can include receiving the read identifiers. In a related aspect, a computer-readable media can store instructions for causing a computer to verify playing card games by the method.
In another aspect, a method of verifying playing card games employs a read sequence of playing card values. The method includes determining an expected set of playing card values for the playing card hand based on the deck sequence of playing card values, a number of hands dealt and a relative position of the playing card hand in an order of dealing; and determining whether the identifiers read from each of the number of playing cards forming the hand of playing cards correspond to the expected set of playing card values for the playing card hand. The method can include reading in sequence an identifier from each of a number of playing cards from which a card game will be dealt, or can include receiving a read sequence of playing card values corresponding to playing cards from which the card game will be dealt. The method can include reading an identifier from each of a number of playing cards forming a hand of playing cards; or can include receiving a collected sequence of playing card values corresponding to the completed hands of playing cards collected from the players and/or dealer. In a related aspect, a computer-readable media can store instructions for causing a computer to verify playing card games by the method.
In a further aspect, a system for verifying playing card games includes a card interface device for reading, writing and/or printing markings on playing cards. The card interface device can be a stand alone device, or can be networked to a host computing system, server, and/or other electronic components. The card interface device can include a reader such as an optical scanner, optical imager or magnetic sensor for reading identifying markings from playing cards. In some aspects, the card interface device can include one or more printing heads, and/or magnetic or other write heads for printing identifying markings on playing cards. The reader and the printing or writing heads can be located in one housing or in separate housings. In some aspects, the card interface device can include a processor configured to generate a pseudo-random sequence of playing card values, and/or a print head controller for printing or writing markings on the playing cards corresponding to the pseudo-random sequence of playing card values.